Ok, so not having much fun here! Car was running great, took off down the road and was off the accelerator.
When I went to accelerate again, nothing.
No lights, no warnings, no coughing, nothing.

The car would crank but would not start.

Towed car home, so far I found that the ECU is not turning on the fuel pump relay and therefore not turning on the pumps. I jumped the pins at the relay and both pumps turn on and sound normal. I have also tested the relay and it works fine by itself. I tried to start with the relay jumped (pumps on), but no go, so I'm guessing the ECU is not seeing something and not allowing the engine to start.

It is at a local garage. They have a very good scan tool and read 10 fuel related codes, that they cannot erase. These codes also do not know pinpoint the problem for them.

So, what would cause the ECU to not turn on the fuel pump relay/start engine?
ECU failure?
Ignition switch?
Faulty key/immobiliser?

Battery was charged and tested. All good.
Any help greatly appreciated, of course this had to happen at Xmas!

Not sure if the electrical systems are the same for the 3.0 and the 4.4 motors, but I had a no start issue that I could not track down. Found out the DME had 3 fuses in the fuse block and one of mine was blown. It was a 7.5amp. So, maybe check your fuses and see what happens. Mine just decided to blow, hasn't done it again in months.

If the engine is cranking over, then it not a key, EWS issue. If the pump is running when you jump the relay then you are missing something else. Have you checked for spark? No spark could be a bad CPS (crank position sensor). Have you checked for injector pulse to the injectors?

This is a diesel. With the fuel pump relays jumped and fuel pumps on, I tried cranking it and it still won't start. So the ECU isn't letting it start for whatever reason. I'm guessing the injectors would not be pulsing either, anyway to test for sure on the diesel?

Ok, SOLVED! As some others had mentioned in other threads, I checked the fuses inside the E-Box located in the engine bay. Sure enough, one 20A fuse was blown, after replacing it, starts no probs. Also driven for 10mins with no immediate failure.

There is a small fuse holder in there that is grey and doesn't really look like a fuse holder at first. When I first looked in there I didn't even think my car had those fuses because I didn't see it.

So unfortunately I had to pay the indy for 6 hrs of trouble shooting, when the diagnosis and scan tools said otherwise. I have the forums to thank for the solution of which I went up to the shop and found myself.

That's the grey fuse holder in the middle of the pic. It is normally clipped on lower, beneath the wiring loom. It's a bit strange to open.
First unclip it from the ebox, then you need to slide the top lid off the fuse holder. It has a couple clips which hold it on, but it will slide off. Hope this helps.

Thought I'd dig this thread up and see if anyone can help. I'm pretty sure tracing it back to this event that my motor has run slower ever since. It was only boosting to about 15psi and recently lost all boost, running very slowly. It all of a sudden went back to how it was running about 12-15psi, still low power. When under load it doesn't control boost well, and fees like it misfires.
Things I have tried:
1. Replaced all injectors (some were leaky)
2. New MAF checked
3. New HPFP regulator
4. Low pressure fuel pump filter changed
5. Boost solenoid checked and vacuum system checked

With INPA, free revving shows requested rail pressure vs actual as matched.
It very much feels like a fuel delivery issue.

There is no codes.

I'm starting to think either a HPFP ( I can't see INPA while driving due bad laptop battery.)
Or, is this some faulty DDE issue?